KR920008650B1 - Method and apparatus for monitoring a lubricating arrangement - Google Patents

Abstract

In a method and a device for controlling a lubrication film between a bearing surface and a shaft surface of the bearing assembly an electric circuit is provided, interconnected between the shaft and the housing of the bearing, in which a thermoelectric voltage is produced by friction heat which is generated at a contact between the shaft and the bearing when a break in the lubrication film occurs, and which termoelectric voltage is used as a voltage source of the electric circuit.

Description

Monitoring method and device of lubrication part

1 is a longitudinal sectional view of a crankshaft bearing of a multicylinder engine having an electrical circuit connected via an external connection.

2 is an enlarged view of one of the bearing locations according to FIG. 1;

3 is a schematic view of a crankshaft with bearings each having one copper wire for the detection of defective bearings.

4 is a state diagram of contact with the shaft via a step wheel for conducting electricity.

5 is a diagram relating to the thermal current measured in the electrical circuit of the bearing portion.

* Explanation of symbols for the main parts of the drawings

1: shaft 2,2 ', 2 ＂: bearing

3 ', 3', 3 ': Slide bearing metal 4, 4', 4 ': White metal layer

5: Lubrication part 6: Bearing stand

The present invention relates to a method for monitoring lubrication at the contact between a rotating shaft and a sliding bearing, in particular between two parts, which are isolated from each other by a lubricant film and which are relatively moving with each other and are of different electrical conductivity materials, and Relates to a device.

For example, when monitoring bearings, especially in large machinery, such as crank bearings in marine diesel engines, lubrication stops immediately before the start of bearing damage and does not lead to breakage of the bearings or crankshaft. It is very important that countermeasures be taken to ensure that the lamps do not come to a halt.

In the case of a sliding bearing on the shaft, a power supply with an external connection is placed in a part in contact with the lubrication part in an electric circuit through which the lubrication part passes.In this case, a circuit resistance reduced in the case of rupture of the lubricating oil film is signaled. It is known to be used as a provision.

The conventional power source installed in the external connection produces a current flowing in the lubrication part in the electric circuit in this case.

In the case of such known lubrication monitoring, despite the fact that it is a good lubricating film, the defect between the shaft and the bearing is still actually harmless, but for a while there is a metallic and low resistance contact, which can cause false alarms. It became. This disadvantageous short time low resistance contact requires monitoring multiple bearings simultaneously and is particularly inconvenient when the short time metal contacts statically overlap.

It is also already known to monitor the bearing temperature with various heat sensors for monitoring the lubrication and to alarm in case of unacceptably high temperatures. Such a thermal sensor can only sense the temperature of the point and in addition, because the sensor cannot reach close enough to the bearing surface for strength reasons, there is a time delay until the thermal current reaches from the damaged part to the thermal sensor. .

As is known from VDI-Periodical Publications 118, 1976, 11, pages 517-524, short metallic contacts are formed by the surface roughness of the members moving with each other, ie located in the millimeter range and short It is formed by the micro ridge generating the thermoelectric power generated in the. This short time thermoelectric power is used to measure the temperature occurring during metal contact in the microridges.

Each micro ridge is heated at the time of contact, producing total heat of heat, and the lifetime of the total heat of light is shorter than 0.1 microseconds. In the microridges, such total heat of light is not only displayed by a fairly rapid display member such as, for example, cathode ray oscilloscope. Such thermal currents in the micro ridges are generated in several normal sliding bearings where intermittent contact is smoothly lubricated in the micro ridges and thus is not a definite indication for lack of lubricating material to indicate bearing damage.

In such micro ridges, sufficient thermal energy is not released because the sliding members are heated to vaporize the lubricant existing between the sliding bearing members. Also, in a sliding bearing, a plurality of micro ridges distributed over the entire bearing surface are in contact at the same time so that some of them achieve precisely high total heat of light, for example, while the other part is in flat contact but is heated. Due to this fact, the short-circuited current through the unheated microridges generated by the thermoelectric power in the heated microridges is not guided outward. For this reason, reliable monitoring of lubrication is impossible by the measurement of the thermoelectric power in the microridges. The detection of the average temperature by the measurement of the average thermoelectric power also cannot reliably explain whether or not the frictional heat that causes heating damage in the bearing is sufficiently released.

The object of the present invention is to use the thermal power generated during the metallic contact of the sliding bearing member, so that when the risk of damage to the body due to the sliding bearing member, the indication of a lack of lubrication is made, and an error of error is reliably excluded. To monitor where to lubricate.

Means of the method of the present invention, which has been devised to solve the above-mentioned problems, are provided with a voltage source and an external connection line, so that the members of both methods are placed in a current circuit coming out of the lubricating oil itself, and the current circuit resistance is reduced in case of breakage of the lubricating film. It is used for signal generation, and the contact between the two sliding bearing members on the large surface caused by the lack of lubrication and the thermal contact generated by the frictional heat at the time of breakdown of the lubricating film are reported. When generated, a strong current is generated through an electrical connection line on the outside of the current circuit formed as a low resistance suitable for the contact portion on the large surface, so that the voltage drop in the resistance of the external connection line described above is used again as a voltage source. To measure and also emit alarms and / or switching signals, in this case When lead to peak voltage at the time, until the time the frequency of the voltage peak will occur, and / or until there is a tendency to increase the amplitude to suppress the alarm.

Again, the constituent means of the present invention, which has been devised to solve the above-mentioned problems, is characterized by the fact that the electrical resistance or the ignition for measuring the voltage drop between the bearing member at the correct position of the lubrication place and the casing or bearing stand which are located separately at the lubrication place. One wire rod formed of a material different from the material of the bearing member provided with a threshold is provided.

The signal-defined thermocouples at the contacts are, for example, in the case of sliding bearings, mounted on shafts and bearing boxes made of steel, and also made of sliding layers which are generally formed of soft iron. Since the electrical connection wire on the outside of the current circuit is formed as a low resistance, only the contact part on the large surface existing at the time of danger, and also the contact part of the low resistance is sufficiently changed by the frictional energy to heat change generated here. A strong current is generated and this current is large enough to cause a voltage drop which enables evaluation in the resistance of the outer low resistance connecting line. In this case, the resistance value of the outer low resistance connecting line corresponds to the contact portion on the large surface.

Lubrication part monitoring according to the present invention significantly prevents the occurrence of false alarms. This is because the sensing device has low resistance due to metallic contact between the shaft and the soft iron bearing layer on the one side of the current circuit in case of lubrication film breakage, and on the other side, the frictional heat at the same time in the contact occurs in this case. Because only responds. Since both effects come together, a thermal current that emits an alarm signal flows only when the voltage in the current circuit, which becomes low resistance when the lubricant film breaks, falls.

In general, when the lubricating oil film ruptures due to the extremely high force applied to the bearing, a very high frictional force is generated so that heat cannot flow out to the connection part of the bearing in the same manner as new heat is transferred from the point of occurrence of the metal contact point. The friction zone produces a large temperature gradient. The difference in thermoelectric power resulting from this temperature gradient and the signal current flowing through the low-resistance electric circuit are correspondingly high, resulting in a clear and clear alarm signal in case of failure. At the moment of rupture of the lubricating oil film, a high temperature appears immediately at the point of contact, and this high temperature suddenly causes thermoelectric power in the electrical circuit, so that the signal emission also takes place without delay.

In the present invention, it is not possible to form a thermocouple that different metals which are in contact with in a large area can actually use, and the temperature which generates a heat signal over the entire area of the parts overlapped with each other is dominant. The thermocouple produces a usable voltage since it must be. Because of the different temperatures that are unavoidable at various points of contact over a large area, different thermoelectric power may be internally shorted here. Surprisingly, the present invention has acknowledged that the above facts do not coincide in the bearing section, where heating, for example, in the case of large area contact of two different materials of the shaft and the beary, also first appears locally only at the time of rupture of the lubricating oil film. This is because, in this case, the lubricant film always has a small hot spot outside the film, and as a result, an electrical short circuit of the thermoelectric power generated at the hot spot is prevented due to the insulating action of the lubricant film. This makes it possible to draw out the thermoelectric power to the outside for monitoring the lubrication part.

In addition, disturbance electromotive force may appear in the electric circuit even in the case of lubrication without problems in the monitoring unit. In this case, for example, galvanic voltage can be a problem, and this galvanic voltage is generated when a lubricant with several metals forms a galvanic element. The disturbance electromotive force is generated from a high resistance power supply and can be mistaken as if the thermal power exists. In order to eliminate this disturbance electromotive force it has been proposed to short circuit this electrical circuit to external wiring via a predetermined low resistance. There is very little current in this circuit from a high-resistance power supply, so only a small voltage gradient is produced at the low resistance of the external wiring, which is not critical for the disturbance voltage. On the other hand, in the case of lubricating oil film, low resistance thermocouples generate very high signal currents, which cause a correspondingly high voltage gradient in the external wiring of the circuit, which results in a ratio of signal processing voltage to disturbance voltage. Very large

The voltage gradient is continuously measured at the electrical resistance of the external connection of the electrical circuit and an alarm signal or a switching signal is generated when the voltage gradient rises above a predetermined limit. If a rupture of the lubricating oil film occurs and the generated thermal power exceeds a predetermined limit, it is safeguarded through the alarm release so that countermeasures can be taken before the bearing damage occurs. Along with the alarm, the drive to the moving part in the bearing part can also be automatically attenuated or blocked by simultaneous control signals.

If an alarm is triggered by a short-term voltage advantage over the threshold and the alarm release tends to increase in amplitude and is sustained until a predetermined temporal frequency appears, then the metal contact of both non-hazardous bearing parts of the short-term Even in those cases where thermal power is generated, additional stability can be obtained for false alarms.

If a number of lubrication units installed in one common unit, for example the bearing part of a crankshaft of a multicylinder engine, or a number of separate bearings, for example motors and drive gears, must also be monitored simultaneously in the electrical circuit, The electrical circuit for common identification of the bearings shows a number of branch lines connected in parallel through each lubrication part. After signal emission, the bearings sending signals are simply identified by comparison with the measurement of the respective bearing temperatures.

In this case, monitoring is the simplest means if each copper wire between the bearing part and the casing or between the bearing body to form a thermocouple current circuit is used to compare with the continuous measurement of each bearing temperature. Only in the copper wire of the alarm bearing, high signal current flows compared to other bearings, and this signal current can be used directly for the indication of damage part.

In the case of lubrication monitoring in the bearing of the shaft, the electrical circuit can be connected to the external connection via a sliding contact that is normally in contact with the rotating shaft. In the above sliding contacts, particularly because of high rotational speeds and undesired wear in the case of large diameter shafts, the current circuit passes around the shaft through electrically running stepped wheels on the conductive shaft, and at the small wheel stage the circuit It is also proposed to make the sliding contact connected to the external connection work.

Due to the conductive step wheels as a result, the wear and at the same time the electrical resistance fluctuations occurring in the sliding contact can be kept low.

In addition, in order to produce a measurement result irrespective of the polarization of the thermoelectric power and the thermal characteristics of each material pair, it is proposed to connect an amplifier which emits a strong signal regardless of the polarization in the circuit in the electric circuit.

Since the thermal current flowing in the low resistance circuit can have a very large value, it is possible to use the magnetic field of the thermal current as a measuring effect. For this purpose, instead of a resistor, a relay's low resistance reel is hypothesized to be external to the circuit. The relay is adjusted to respond in the case of a constant current.

The present invention will be described in detail with reference to the drawings.

In FIGS. 1 and 2 of the crank drive for the multicylinder-piston engine shown briefly, the crankshaft 1 has a bearing 2, 2 'and 2 ＂having sliding bearing metals 3, 3' and 3＂. Supported by). In order to obtain good activity, this sliding bearing metal has its own shafts in contact with its shaft (1) embedded in white metal layers (4, 4 'and 4 ＂), in which case this white metal layer (4) and shaft (1) The lubricating oil film 5 existing in between prevents overheating operation of the bearing. The sliding bearing metals 3, 3 ′, 3 ′ are supported by bearing stands 6, 6 ′, 6 ′, which are part of the common casing 7.

For monitoring the lubrication part 5, the bearing parts 3, 4 and the shaft 1 are in an electric circuit 8 passing through the lubrication part 5, which is connected via an external connection 9. It is short-circuited with the low resistance 10 provided inside. The outer connection 9 is fastened to one side by a conductive casing 7 and connected to the shaft 1 made of steel so as to be electrically conductive via the active part 11 on the other side. The electrical circuit 8 passes through the lubrication section 5 and has a plurality of current feeders which are connected in parallel, which are the sliding bearing metals 3, 3 ′, 3 ＂of metal and the height metals 4, 4. All lubrications 5 of the bearings 2, 2 ′ and 2 는 are simultaneously monitored here because they are formed by several bearing posts 6, 6 ′, 6 ＂with 4 ′.

If the lubricating oil film ruptures in the case of a failure in the lubrication part 5, the electric circuit becomes low resistance due to the metal contact between the shaft 1 and the white metal layer 4 appearing in the current feeder, and as a result of the frictional heat generated at this time, At the same time between the steel shaft 1 and the white metal layer 4 of the bearing 2 a high thermoelectric force is generated which is essentially proportional to the frictional horsepower. This thermoelectric power is also transferred at the transition part 12 between the white metal 4 and the bearing metal 3 composed of another metal material and at the transition part 13 between the bearing metal 3 and the bearing base 6 having different materials. Depending on the heat flow and material pairs, the thermoelectric power shown in

The thermal current I flows in the electric circuit 8 which is made low resistance by the generated thermoelectric power, and this thermal current is the voltage drop U in the resistor 10. This signal is conveyed via the amplifier 14 to the indicating device 15, which sends an alarm signal when the threshold is exceeded and, in the case given, a control signal for the engine.

Copper wires 16, 16 'and 16 with voltage meters 17, 17' and 17 ＂on the bearings 2, 2 'and 2 및 shown in FIG. 3 to confirm which of the bearings has sent an alarm. V) is installed. The copper wire 16 is fastened to a bearing metal 3 consisting of a different material on one side and to a casing 7 located away from the lubrication part 5 on the other, thus forming one thermocouple electrical circuit. . Only on the copper wire of the bearing which sends the alarm, a considerably high signal current flows as a result of the temperature difference and this signal current immediately indicates damage.

The electrically conductive step wheel 18 shown in the case of the embodiment according to FIG. 4 rolls around the shaft 1 with the large wheel step 19 and the small wheel step 20 is elastically bearing supported sliding. It is in contact with the contactor 21. The sliding contact 21 is connected to the external connection 9 of the electric circuit 8 and the conductive connection of the shaft 1 is made through the outer shell rolling in contact with the shaft of the large wheel step 19.

From the diagram shown in FIG. 5 relating to the thermal current measured in the electrical circuit of the bearing part, in the case of a lubricating oil film without obstacles in the bearing place, a very small and current 22 flows in the electrical circuit 8 due to the interference voltage. However, if a harmless metal contact occurs between the white metal layer 4 and the shaft 1 by a short time, the short-time current peak 23 generated by the short time is suppressed even when the threshold 24 is exceeded. On the contrary, if the lubricating oil film is ruptured, the current peak is superimposed and the thermal current corresponding to the characteristic curve section 25 is correspondingly severe and as a result an alarm is sent due to the exceeding of the limit 24.

If further heat generation is prevented due to the action taken at the bearing site, the thermoelectric or thermal current returns very quickly and this makes it easy to observe lubrication starting. Elevated bearing temperatures, as confirmed by the test, do not themselves cause any thermoelectric power.

The advantage obtained by the present invention is to significantly suppress the occurrence of false alarms. The generation of an alarm signal occurs immediately at the moment of lubrication film breakage, and this temperature is generated without delay due to the shock of the thermal circuit of the current circuit.

Claims (12)

A method of monitoring the lubrication state at a contact portion between two members made of different conductive materials that are insulated from each other by a lubricating film and move relative to each other, wherein the both members have an outer connection line and exit from the lubrication portion itself. Located in the current circuit, metallic contact which reports the thermal damage and contact between both sliding bearing members on the large surface caused by the lack of lubrication is generated by the heat generated by frictional heat when the lubrication film breaks in the contact portion. At the beginning, it is used as a voltage source to generate a strong current through an electrical connection line on the outside of the current circuit formed with a low resistance suitable for a contact on a large surface, and measure the voltage drop in the resistance of the external connection line. Used to issue an alarm signal, in this case a short time When a voltage peak occurs method for monitoring a lubricating condition, characterized in that for suppressing the alarm until a predetermined temporal frequency of the voltage peak. The method according to claim 1, wherein the thermoelectric power for generating a current flowing through the low resistance outer connecting line is not caused only by the metallic contact of both sliding bearing members, but in a separate transition between different materials of the bearing portion. Method for monitoring the lubrication state, characterized in that generated by the thermal current generated by the friction of the. The method of claim 1 or 2, wherein an alarm signal is issued when the voltage drop measured at low resistance exceeds a predetermined threshold. The bearing according to claim 1, wherein a plurality of lubrication parts are simultaneously monitored in a common constituent unit or separately, and the current circuit has a plurality of branches of parallel connection exiting from the respective lubrication parts, and generates a warning signal. The method for monitoring the lubrication state, which is investigated by measuring and comparing individual bearing temperatures. In the apparatus for implementing the method for monitoring the lubrication state according to claim 1, the bearing member 3, 4 of the lubrication part 5 and the casing 7 or the bearing which are located away from the lubrication part. An electrical resistance or voltage meter 17 for measuring the voltage drop between the dies is provided, and each wire 16 is made of a material different from that of the bearing member. Device. The electric circuit 8 is connected via the conductive step | step 18, The step 19 with the big step | step is rolling on the circumferential surface of the shaft 1, and the small step 20 is carried out. And a sliding contact member (21) connected to the outer connection lines (8, 10, 9, 11) of the current circuits. 7. The lubrication monitoring according to claim 5 or 6, wherein an amplifier 14 is connected to the current circuit 8, and the amplifier generates a positive signal irrespective of the pole of the residual circuit. Device. The device for monitoring lubrication according to claim 5, wherein a low resistance coil of the relay is assembled to the outer connecting line (9) of the current circuit (8). A method of monitoring the lubrication state at a contact portion between two members made of different conductive materials that are insulated from each other by a lubricating film and move relative to each other, wherein the both members have an outer connection line and exit from the lubrication portion itself. Located in the current circuit, metallic contact which reports the thermal damage and contact between both sliding bearing members on the large surface caused by the lack of lubrication is generated by the thermal power generated by the frictional heat at the lubrication film breakage at the contact portion. At the time, it is used as a voltage source to generate a strong current through the electrical connection line on the outside of the current circuit which is initially formed with a low resistance suitable for the contact on the large surface, and measure and switch the voltage drop in the resistance of the external connection line. Used to signal, in this case a short time Suppressing the occurrence of an alarm when a predetermined temporal frequency of the voltage peak occurs when a peak occurs within the lubrication state. A method of monitoring the lubrication state at a contact portion between two members made of different conductive materials that are insulated from each other by a lubricating film and move relative to each other, wherein the both members have an outer connection line and exit from the lubrication portion itself. Located in the current circuit, metallic contact which reports the thermal damage and contact between both sliding bearing members on the large surface caused by the lack of lubrication is generated by the heat generated by frictional heat when the lubrication film breaks in the contact portion. At the time, it is used as a voltage source to generate a strong current through the electrical connection line of the outer side of the current circuit which is initially formed with a low resistance suitable for the contact on the large surface, and measure the voltage drop in the resistance of the outer connection line and alarm Used to signal, in this case a short time When the voltage peaks occur in the method for monitoring a lubricating condition, characterized in that for suppressing the alarm until a tendency to increase in amplitude occur. A method of monitoring the lubrication state at a contact portion between two members made of different conductive materials which are insulated from each other by a lubricating film and move relative to each other, wherein the two members have an outer connection line from the lubrication portion itself. It is located in the outgoing current circuit, and the metallic contact which reports the thermal damage and contact between both sliding bearing members on the large surface caused by the lack of lubrication is caused by the frictional heat at the contact part. At the time of occurrence, it is used as a voltage source to generate a strong current through the electrical connection line of the outer side of the current circuit which is initially formed with a low resistance suitable for the contact part on the large surface, and measure the voltage drop in the resistance of the outer connection line. Used to issue a switching signal, in this case a short time When the voltage peaks occur in the method for monitoring a lubricating condition, characterized in that for suppressing the alarm until a tendency to increase in amplitude occur. 3. A method according to claim 1 or 2, wherein a switching signal is issued when the voltage drop measured at low resistance exceeds a predetermined threshold.

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